Unfold Subtopic Only First Level

[gitcpy]

When there is a lot things in a md file, it would make the map very large.
And if there are only two actions, ' fold' and 'unfold' , for map，
I think it is an optimization to add a right click of manipultion menu for more actions,
such as unfold all , or unfold subtopic of first level.
Could you please think about it?
It would be a better experience for users, thanks.